Wireless signal identification

ABSTRACT

Technologies are generally described for identifying whether a propagation path between a mobile device and an access point is line-of-sight. In some examples, a method performed under control of a mobile device may include receiving, from an access point, a first signal transmitted at a first frequency band; receiving, from the access point, a second signal transmitted at a second frequency band; measuring a difference value between propagation properties of the first signal and the second signal; and identifying whether a propagation path between the mobile device and the access point is line-of-sight or non-line-of-sight based at least in part on the difference value.

BACKGROUND

Location estimation in wireless technology has attracted great interestsin recent research, because it is an important task in variousapplications of wireless communications. Further, attention ondeveloping an indoor location technology based on the wireless localarea network (WLAN) is gradually increasing while the population of theWLAN is growing. The superiority in using this technique can utilize theexisting hardware without affecting the original network accessfunction, and will also create a popular value added.

SUMMARY

In an example, a method performed under control of a mobile device mayinclude receiving, from an access point, a first signal transmitted at afirst frequency band; receiving, from the access point, a second signaltransmitted at a second frequency band; measuring a difference valuebetween propagation properties of the first signal and the secondsignal; and identifying whether a propagation path between the mobiledevice and the access point is line-of-sight or non-line-of-sight basedat least in part on the difference value.

In another example, a mobile device may include a receiver unitconfigured to receive, from an access point, a first signal transmittedat a first frequency band and a second signal transmitted at a secondfrequency band; a difference value calculation unit configured tocalculate a difference value between propagation properties of the firstsignal and the second signal; an identification unit configured toidentify whether a propagation path between the mobile device and theaccess point is line-of-sight or non-line-of-sight based at least inpart on the difference value; and a position calculation unit configuredto calculate a current position of the mobile device based at least inpart on the first signal and/or the second signal.

In yet another example, a computer-readable storage medium may storethereon computer-executable instructions that, in response to execution,cause a mobile device to perform operations, including transmitting, toan access point, a probe request signal at a first frequency band;receiving, from the access point, a probe response signal transmitted atthe first frequency band in response to the probe request signal;receiving, from the access point, a beacon signal transmitted at asecond frequency band; measuring a difference value between propagationproperties of the probe response signal and the beacon signal; andidentifying whether a propagation path between the mobile device and theaccess point is line-of-sight or non-line-of-sight based at least inpart on the difference value.

The foregoing summary is illustrative only and is not intended to be inany way limiting. In addition to the illustrative aspects, embodiments,and features described above, further aspects, embodiments, and featureswill become apparent by reference to the drawings and the followingdetailed description.

BRIEF DESCRIPTION OF THE FIGURES

The foregoing and other features of this disclosure will become moreapparent from the following description and appended claims, taken inconjunction with the accompanying drawings. Understanding that thesedrawings depict only several embodiments in accordance with thedisclosure and are, therefore, not to be considered limiting of itsscope, the disclosure will be described with additional specificity anddetail through use of the accompanying drawings, in which:

FIG. 1 shows an illustrative example of a wireless communicationenvironment including a mobile device and an access point, arranged inaccordance with at least some embodiments described herein;

FIG. 2 shows a block diagram of an example architecture of a mobiledevice configured to implement a wireless signal identification scheme,arranged in accordance with at least some embodiments described herein;

FIG. 3 shows a block diagram of another example architecture of a mobiledevice configured to implement a wireless signal identification scheme,arranged in accordance with at least some embodiments described herein;

FIG. 4 shows a block diagram of an example architecture of a signalidentification manager to implement a wireless signal identificationscheme, arranged in accordance with at least some embodiments describedherein;

FIG. 5 shows an illustrative example of an indoor place in which amobile device and multiple access points are located, arranged inaccordance with at least some embodiments described herein;

FIG. 6 shows an example flow diagram of a process to implement awireless signal identification scheme, arranged in accordance with atleast some embodiments described herein;

FIG. 7 illustrates an example computer program product that may beutilized to implement a wireless signal identification scheme, arrangedin accordance with at least some embodiments described herein; and

FIG. 8 is a block diagram illustrating an example computing device thatmay be utilized to implement a wireless signal identification scheme,arranged in accordance with at least some embodiments described herein.

DETAILED DESCRIPTION

In the following detailed description, reference is made to theaccompanying drawings, which form a part hereof. In the drawings,similar symbols typically identify similar components, unless contextdictates otherwise. The illustrative embodiments described in thedetailed description, drawings, and claims are not meant to be limiting.Other embodiments may be utilized, and other changes may be made,without departing from the spirit or scope of the subject matterpresented herein. It will be readily understood that the aspects of thepresent disclosure, as generally described herein, and illustrated inthe drawings, can be arranged, substituted, combined, separated, anddesigned in a wide variety of different configurations, all of which areexplicitly contemplated herein.

This disclosure is generally drawn, inter alia, to methods, apparatuses,systems, devices, and computer program products related to identify awireless signal from an access point. Further, technologies are hereingenerally described for identifying whether a propagation path between amobile device and an access point is line-of-sight or non-line-of-sightbased on properties of multiple signals each transmitted, from theaccess point, at a different frequency band to provide more accurateposition information of the mobile device.

In some examples, a mobile device may be configured to receive, from anaccess point, a first signal and a second signal respectivelytransmitted at a first frequency band and a second frequency band. Insuch cases, propagation properties of the first frequency band and thesecond frequency band may be different. By way of example, but notlimitation, the first frequency band may be an industry-science-medical(ISM) band of about 2.4 GHz and the second frequency band may be aunlicensed national information infrastructure (UNII) band of about 5GHz. By way of non-limiting example, the propagation property mayinclude, but not limited thereto, a propagation loss, a reflectionproperty, a diffraction property or an absorption property.

The mobile device may be configured to measure a difference valuebetween the propagation properties of the first signal and the secondsignal. Further, the mobile device may be configured to identify whethera propagation path between the mobile device and the access point isline-of-sight or non-line-of-sight based at least in part on thedifference value. By way of example, but not limitation, a differencevalue of propagation losses between the ISM band and the UNII band isnormally about 6.8 dB. However, the difference value may be higher thanthe normal value when there are obstacles (such as, for example, walls,furniture, etc.) between the mobile device and the access point (thatis, the propagation path between the mobile device and the access pointis non-line-of-sight). The mobile device may determine that thepropagation path between the mobile device and the access point isnon-line-of-sight when the difference value is higher than the normalvalue.

In some examples, the mobile device may be further configured toreceive, from the access point, a propagation environment signal, whichmay include, for example, at least one of information about a layout ofa building, in which the access point and the mobile device are located,or information about materials of the building. In such cases, themobile device may be further configured to identify whether thepropagation path is line-of-sight or non-line-of-sight based on thepropagation environment signal.

In some examples, the first signal and/or the second signal transmittedfrom the access point may include location information of the accesspoint, and the mobile device may be configured to calculate a currentposition of the mobile device based on the location information of theaccess point. Further, the mobile device may use the locationinformation to calculate the current position of the mobile device onlywhen the propagation path is identified as being line-of-sight. By wayof example, but not limitation, the mobile device may receive signalsfrom multiple access points (including the access point) and calculatethe current position of the mobile device using triangulation based onrespective location information of the multiple access points.

FIG. 1 shows an illustrative example of a wireless communicationenvironment 100 including a mobile device 110 and an access point 120,arranged in accordance with at least some embodiments described herein.For example, but not as a limitation, mobile device 110 may refer to atleast one of a smart phone, a portable device, a notebook computer, atablet device, a phablet device, a personal computer or a personalcommunication terminal, such as PCS (Personal Communication System), GMS(Global System for Mobile communications), PDC (Personal DigitalCellular), or PDA (Personal Digital Assistant).

Access point 120 may be configured to provide wireless communicationcapability to one or more devices, including mobile device 110, locatedwithin its communication range. Access point 120 may be configured totransmit, to mobile device 110, a first signal 130 at a first frequencyband. Further, access point 120 may be configured to transmit, to mobiledevice 110, a second signal 140 at a second frequency band that isdifferent from the first frequency band. In some embodiments, accesspoint 120 may receive a probe request signal from mobile device 110 and,in response to the probe request signal, transmit, to mobile device 110,first signal 130 (which may be a probe response signal) at the firstfrequency band. In the present disclosure, it is assumed that apropagation property (such as, for example, a propagation loss, areflection property, a diffraction property or an absorption property)of the first frequency band is different from that of the secondfrequency band.

In some embodiments, mobile device 110 may be configured to receivefirst signal 130 at the first frequency band and second signal 140 atthe second frequency band. Mobile device 110 may be configured tomeasure a propagation property of first signal 130 and that of secondsignal 140 and measure a difference value between propagation propertiesof first signal 130 and second signal 140. Mobile device 110 may then beconfigured to identify whether a propagation path between mobile device110 and access point 120 is line-of-sight or non-line-of-sight based onthe measured difference value. In some embodiments, mobile device 110may compare the measured difference value with a normal difference valueof free-space propagation. In such cases, when the measured differencevalue is higher than the normal difference value of free-spacepropagation, mobile device 110 may determine that the propagation pathbetween mobile device 110 and access point 120 is non-line-of-sight.

By way of non-limiting example, access point 120 may include awireless-fidelity (Wi-Fi) access point based on IEEE 802.11a/b/g/n/ac.Such Wi-Fi access point is capable to use an ISM band and a UNII band toperform wireless communication. Available frequency resources at theWi-Fi access point may include fourteen (14) channels at the ISM band(2.412 to 2.472 GHz; represented by 2.4 GHz) and twenty four (24)channels at the UNII band (5.180 to 5.825 GHz; represented by 5 GHz). Insuch examples, the first frequency band may correspond to the ISM bandand the second frequency band may correspond to the UNII band. Further,mobile device 110 may be equipped with a Wi-Fi chipset, which canprovide wireless communication capability at both of the ISM band andthe UNII band, so that mobile device 110 may be able to perform wirelesscommunication with access point 120 through both of the ISM band and theUNII band.

Propagation properties in the ISM band and the UNII band may haveinherent characteristics due to the difference in frequency bands, asbelow. For example, the difference of propagation losses between 2.4 GHzand the 5 GHz is normally around 6.8 dB. If the difference ofpropagation losses is over 15 dB, mobile device 110 may determine thatthe propagation path between mobile device 110 and access point 120 isnon-line-of-sight.

In some embodiments, mobile device 110 may be configured to concurrentlyreceive first signal 130 at the first frequency band and second signal140 at the second frequency band. In some other embodiments, mobiledevice 110 may perform an active scanning (for example, transmitting aprobe request signal to access point 120) at the first frequency andreceive first signal 130 (for example, a probe response signal) fromaccess point 120. In such cases, mobile device 110 may then perform apassive scanning (for example, receiving a beacon signal from accesspoint 120) at the second frequency band.

In some embodiments, at least one of first signal 130 or second signal140 may be configured to include location information of access point120. Mobile device 110, which has received first signal 130 and secondsignal 140, may calculate a current position of mobile device 110 usingthe location information of access point 120 together with locationinformation of one or more other access points. By way of example, butnot limitation, mobile device 110 may calculate the current positionusing triangulation based on respective location information of themultiple access points. In some embodiments, mobile device 110 may beconfigured to calculate the current position based only on access pointsthat are located in a line-of-sight path. That is, when mobile device110 determines that the propagation path between mobile device 110 andaccess point 120 is non-line-of-sight, mobile device 110 may not use thelocation information of access point 120 to calculate the currentposition of mobile device 110.

In some examples, mobile device 110 may be configured to receive apropagation environment signal from access point 120. In the examples ofusing the ISM band and the UNII band, mobile device 110 may receive thepropagation environment signal at the ISM band. By way of example, butnot limitation, the propagation environment signal may include at leastone of information about a layout of a building, in which mobile device110 and access point 120 are located, or information about materials ofthe building. In such cases, mobile device 110 may be further configuredto identify whether the propagation path is line-of-sight ornon-line-of-sight based on the propagation environment signal.

FIG. 2 shows a block diagram of an example architecture of mobile device110 configured to implement a wireless signal identification scheme,arranged in accordance with at least some embodiments described herein.Reference may be made to the embodiments depicted and described withreference to FIG. 1.

As depicted, mobile device 110 may include a receiver unit 210, adifference value calculation unit 220, an identification unit 230 and aposition calculation unit 240. Although illustrated as discretecomponents, various components may be divided into additionalcomponents, combined into fewer components, or eliminated while beingcontemplated within the scope of the disclosed subject matter. It willbe understood by those skilled in the art that each function and/oroperation of the components may be implemented, individually and/orcollectively, by a wide range of hardware, software, firmware, orvirtually any combination thereof.

Receiver unit 210 may be configured to receive, from access point 110,first signal 130 at the first frequency band and second signal 140 atthe second frequency band. In some embodiments, receiver unit 210 mayreceive first signal 130 and second signal 140 concurrently. In someembodiments, receiver unit 210 may receive first signal 130 first andthen second signal 140 later. By way of example, the first frequencyband may be an ISM band of 2.4 GHz and the second frequency band may bea UNII band of 5 GHz. In some embodiments, receiver unit may be furtherconfigured to receive a propagation environment signal from access point120. The propagation environment signal may be received at the firstfrequency band. By way of example, but not limitation, the propagationenvironment signal may include at least one of information about alayout of a building, in which mobile device 110 and access point 120are located, or information about materials of the building.

Difference value calculation unit 220 may be configured to measure apropagation property of first signal 130 and that of second signal 140and calculate a difference value between propagation properties of firstsignal 130 and second signal 140. By way of example, but not limitation,the propagation property may include a propagation loss, a reflectionproperty, a diffraction property or an absorption property.

Identification unit 230 may be configured to identify whether apropagation path between mobile device 110 and access point 120 isline-of-sight or non-line-of-sight based on the calculated differencevalue. In some embodiments, identification unit 230 may compare thecalculated difference value with a normal difference value of free-spacepropagation. In such cases, when the calculated difference value ishigher than the normal difference value of free-space propagation,identification unit 230 may determine that the propagation path betweenmobile device 110 and access point 120 is non-line-of-sight. In someembodiments, identification unit 230 may further make a reference to thepropagation environment signal received by receiver unit 210 for thedetermination, and such reference may contribute to a more precisedetermination.

Position calculation unit 240 may be configured to calculate a currentposition of mobile device 110 based at least in part on first signal 130and/or second signal 140. In such cases, at least one of first signal130 or second signal 140 may include location information of accesspoint 120. By way of example, but not limitation, mobile device 110 maycalculate the current position using triangulation based on respectivelocation information of multiple access points including access point120. In some embodiments, position calculation unit 240 may beconfigured to calculate the current position based only on access pointsthat are located in a line-of-sight path. That is, when identificationunit 230 determines that the propagation path between mobile device 110and access point 120 is non-line-of-sight, position calculation unit 240may not use the location information of access point 120 to calculatethe current position of mobile device 110.

FIG. 3 shows a block diagram of another example architecture of mobiledevice 110 configured to implement a wireless signal identificationscheme, arranged in accordance with at least some embodiments describedherein. Reference may be made to the embodiments depicted and describedwith reference to FIGS. 1 and 2.

As depicted, mobile device 110 may include a signal identificationmanager 310, an operating system 320 and a processor 330. Signalidentification manager 310 may be adapted to operate on operating system320 such that the wireless signal identification scheme, as describedherein, may be provided. Operating system 320 may allow signalidentification manager 310 to manipulate processor 330 to implement thewireless signal identification scheme as described herein.

FIG. 4 shows a block diagram of an example architecture of signalidentification manager 310 to implement a wireless signal identificationscheme, arranged in accordance with at least some embodiments describedherein. Reference may be made to the embodiments depicted and describedwith reference to FIGS. 1 to 3.

As depicted, signal identification manager 310 may include a differencevalue calculation component 410 and an identification component 420.Difference value calculation component 410 may be adapted to calculate adifference value between propagation properties of first signal 130 andsecond signal 140, in accordance with various example methods asdescribed above. Identification component 420 may be adapted to identifywhether a propagation path between mobile device 110 and access point120 is line-of-sight or non-line-of-sight based at least in part on thecalculated difference value, in accordance with various example methodsas described above.

FIG. 5 shows an illustrative example of an indoor place in which amobile device 510 and multiple access points 521, 522, 523, 524 and 525are located, arranged in accordance with at least some embodimentsdescribed herein.

As depicted, access points 521 to 525 are located in various positionsin the indoor place, in which a hallway wall 530, a room 540 and a block550 are arranged to divide the indoor place. Mobile device 510, which islocated in the indoor place, may receive signals from access points 521to 525.

In some embodiments, mobile device 510 may receive a first signal at afirst frequency band and a second signal at a second frequency band fromeach of access points 521 to 525. The first signal and the second signalmay be received at mobile device 510 concurrently or sequentially.Mobile device 510 may then measure and/or calculate a difference valuebetween propagation properties of the first signal and the second signalfor each of access points 521 to 525 and identify whether eachpropagation path between mobile device 510 and each of access points 521to 525 is line-of-sight or non-line-of-sight based on correspondingdifference value.

As depicted in FIG. 5, there are no obstacles between mobile device 510and access points 521 to 523, and thus, it may be determined that thepropagation paths between mobile device 510 and access points 521 to 523are line-of-sight. However, access points 524 and 525 are blocked byhallway wall 530 and room 540, respectively, and the propagation pathsbetween mobile device 510 and access points 524 and 525 arenon-line-of-sight. In some embodiments, mobile device 510 may receivelocation information from each of access points 521 to 523, of which thepropagation path is line-of-sight, to calculate a current position ofmobile device 510 using triangulation based the received locationinformation.

FIG. 6 shows an example flow diagram of a process to implement awireless signal identification scheme, arranged in accordance with atleast some embodiments described herein.

Process 600 may be implemented by a mobile device such as mobile device110 including at least some of receiver unit 210, difference valuecalculation unit 220, identification unit 230 or position calculationunit 240. Process 600 may also be implemented by computer programs orprogram modules that may be adapted to provide a wireless signalidentification scheme and hosted by mobile device 110, such as signalidentification manager 310 including difference value calculationcomponent 410 and identification component 420. Thus, reference may bemade to the embodiments depicted and described with reference to FIGS.1-5. Process 600 may include one or more operations, actions, orfunctions as illustrated by one or more blocks 610, 620, 630 and/or 640.Although illustrated as discrete blocks, various blocks may be dividedinto additional blocks, combined into fewer blocks, or eliminated,depending on the desired implementation. Processing may begin at block610.

At block 610 (Receive a First Signal Transmitted at a First FrequencyBand), mobile device 110 and/or receiver unit 210 may receive, fromaccess point 120, first signal 130 at the first frequency band. By wayof example, but not limitation, the first frequency band may be an ISMband. Processing may continue from block 610 to block 620.

At block 620 (Receive a Second Signal Transmitted at a Second FrequencyBand), mobile device 110 and/or receiver unit 210 may receive, fromaccess point 120, second signal 140 at the second frequency band. By wayof example, but not limitation, the second frequency band may be a UNIIband. Processing may continue from block 620 to block 630.

At block 630 (Calculate a Difference Value between PropagationProperties of the First and Second Signals), mobile device 110 and/ordifference value calculation unit 220 may measure a propagation propertyof first signal 130 and that of second signal 140. Then, mobile device110 and/or difference value calculation unit 220 may measure and/orcalculate a difference value between the propagation properties of firstsignal 130 and second signal 140. By way of non-limiting example, thepropagation property may include, but not limited thereto, a propagationloss, a reflection property, a diffraction property or an absorptionproperty. Processing may continue from block 630 to block 640.

At block 640 (Identify Whether a Propagation Path is Line-of-Sight),mobile device 110 and/or identification unit 230 may identify whether apropagation path between mobile device 110 and access point 120 isline-of-sight or non-line-of-sight based on the difference value. Insome embodiments, mobile device 110 and/or identification unit 230 maycompare the difference value with a normal difference value offree-space propagation. In such cases, when the difference value iswithin a predetermined range of the normal difference value offree-space propagation, mobile device 110 and/or identification unit 230may determine that the propagation path between mobile device 110 andaccess point 120 is line-of-sight.

One skilled in the art will appreciate that, for this and otherprocesses and methods disclosed herein, the functions performed in theprocesses and methods may be implemented in differing order.Furthermore, the outlined steps and operations are only provided asexamples, and some of the steps and operations may be optional, combinedinto fewer steps and operations, or expanded into additional steps andoperations without detracting from the essence of the disclosedembodiments.

FIG. 7 illustrates an example computer program product 700 that may beutilized to implement a wireless signal identification scheme, arrangedin accordance with at least some embodiments described herein.

As depicted, program product 700 may include a signal bearing medium702. Signal bearing medium 702 may include one or more instructions 704that, when executed by, for example, a processor of mobile device 110may provide the functionality described above with respect to FIGS. 1-6.By way of example, instructions 704 may include: one or moreinstructions for receiving, from an access point, a first signaltransmitted at a first frequency band; or one or more instructions forreceiving, from the access point, a second signal transmitted at asecond frequency band; or one or more instructions for calculating(and/or measuring) a difference value between propagation properties ofthe first signal and the second signal; or one or more instructions foridentifying whether a propagation path between the mobile device and theaccess point is line-of-sight or non-line-of-sight based at least inpart on the difference value.

In some implementations, signal bearing medium 702 may encompass acomputer-readable medium 706, such as, but not limited to, a hard diskdrive, a CD, a DVD, a digital tape, memory, etc. In someimplementations, signal bearing medium 702 may encompass a recordablemedium 708, such as, but not limited to, memory, read/write (R/W) CDs,R/W DVDs, etc. In some implementations, signal bearing medium 702 mayencompass a communications medium 710, such as, but not limited to, adigital and/or an analog communication medium (e.g., a fiber opticcable, a waveguide, a wired communications link, a wirelesscommunication link, etc.). Thus, for example, program product 700 may beconveyed to one or more modules of electronic device 120 by an RF signalbearing medium 702, where the signal bearing medium 702 is conveyed by awireless communications medium 710 (e.g., a wireless communicationsmedium conforming with the IEEE 802.11 standard).

FIG. 8 is a block diagram illustrating an example computing device 800that may be utilized to implement a wireless signal identificationscheme, arranged in accordance with at least some embodiments describedherein.

In a very basic configuration 802, computing device 800 typicallyincludes one or more processors 804 and a system memory 806. A memorybus 808 may be used for communicating between processor 804 and systemmemory 806.

Depending on the desired configuration, processor 804 may be of any typeincluding but not limited to a microprocessor (μP), a microcontroller(μC), a digital signal processor (DSP), or any combination thereof.Processor 804 may include one or more levels of caching, such as a levelone cache 810 and a level two cache 812, a processor core 814, andregisters 816. An example processor core 814 may include an arithmeticlogic unit (ALU), a floating point unit (FPU), a digital signalprocessing core (DSP Core), or any combination thereof. An examplememory controller 818 may also be used with processor 804, or in someimplementations memory controller 818 may be an internal part ofprocessor 804.

Depending on the desired configuration, system memory 806 may be of anytype including but not limited to volatile memory (such as RAM),non-volatile memory (such as ROM, flash memory, etc.) or any combinationthereof. System memory 806 may include an operating system 820, one ormore applications 822, and program data 824.

Application 822 may include an signal identification algorithm 826 thatmay be arranged to perform the functions as described herein includingthe actions described with respect to mobile device 110 architecture asshown in FIGS. 2-4 or including the actions described with respect tothe flow chart shown in FIG. 6. Program data 824 may include any datathat may be useful for providing the signal identification scheme as isdescribed herein. In some examples, application 822 may be arranged tooperate with program data 824 on an operating system 820 such that thewireless signal identification scheme as described herein may beprovided.

Computing device 800 may have additional features or functionality, andadditional interfaces to facilitate communications between basicconfiguration 802 and any required devices and interfaces. For example,a bus/interface controller 830 may be used to facilitate communicationsbetween basic configuration 802 and one or more data storage devices 832via a storage interface bus 834. Data storage devices 832 may beremovable storage devices 836, non-removable storage devices 838, or acombination thereof. Examples of removable storage and non-removablestorage devices include magnetic disk devices such as flexible diskdrives and hard-disk drives (HDD), optical disk drives such as compactdisk (CD) drives or digital versatile disk (DVD) drives, solid statedrives (SSD), and tape drives to name a few. Example computer storagemedia may include volatile and nonvolatile, removable and non-removablemedia implemented in any method or technology for storage ofinformation, such as computer readable instructions, data structures,program modules, or other data.

System memory 806, removable storage devices 836 and non-removablestorage devices 838 are examples of computer storage media. Computerstorage media includes, but is not limited to, RAM, ROM, EEPROM, flashmemory or other memory technology, CD-ROM, digital versatile disks (DVD)or other optical storage, magnetic cassettes, magnetic tape, magneticdisk storage or other magnetic storage devices, or any other mediumwhich may be used to store the desired information and which may beaccessed by computing device 800. Any such computer storage media may bepart of computing device 800.

Computing device 800 may also include an interface bus 840 forfacilitating communication from various interface devices (e.g., outputdevices 842, peripheral interfaces 844, and communication devices 846)to basic configuration 802 via bus/interface controller 830. Exampleoutput devices 842 include a graphics processing unit 848 and an audioprocessing unit 850, which may be configured to communicate to variousexternal devices such as a display or speakers via one or more A/V ports852. Example peripheral interfaces 844 include a serial interfacecontroller 854 or a parallel interface controller 856, which may beconfigured to communicate with external devices such as input devices(e.g., keyboard, mouse, pen, voice input device, touch input device,etc.) or other peripheral devices (e.g., printer, scanner, etc.) via oneor more I/O ports 858. An example communication device 846 includes anetwork controller 860, which may be arranged to facilitatecommunications with one or more other computing devices 862 over anetwork communication link via one or more communication ports 864.

The network communication link may be one example of a communicationmedia. Communication media may typically be embodied by computerreadable instructions, data structures, program modules, or other datain a modulated data signal, such as a carrier wave or other transportmechanism, and may include any information delivery media. A “modulateddata signal” may be a signal that has one or more of its characteristicsset or changed in such a manner as to encode information in the signal.By way of example, and not limitation, communication media may includewired media such as a wired network or direct-wired connection, andwireless media such as acoustic, radio frequency (RF), microwave,infrared (IR) and other wireless media. The term computer readable mediaas used herein may include both storage media and communication media.

The present disclosure is not to be limited in terms of the particularembodiments described in this application, which are intended asillustrations of various aspects. Many modifications and variations canbe made without departing from its spirit and scope, as will be apparentto those skilled in the art. Functionally equivalent methods andapparatuses within the scope of the disclosure, in addition to thoseenumerated herein, will be apparent to those skilled in the art from theforegoing descriptions. Such modifications and variations are intendedto fall within the scope of the appended claims. The present disclosureis to be limited only by the terms of the appended claims, along withthe full scope of equivalents to which such claims are entitled. It isto be understood that this disclosure is not limited to particularmethods, reagents, compounds, compositions or biological systems, whichcan, of course, vary. It is also to be understood that the terminologyused herein is for the purpose of describing particular embodimentsonly, and is not intended to be limiting.

With respect to the use of substantially any plural and/or singularterms herein, those having skill in the art can translate from theplural to the singular and/or from the singular to the plural as isappropriate to the context and/or application. The varioussingular/plural permutations may be expressly set forth herein for sakeof clarity.

It will be understood by those within the art that, in general, termsused herein, and especially in the appended claims (e.g., bodies of theappended claims) are generally intended as “open” terms (e.g., the term“including” should be interpreted as “including but not limited to,” theterm “having” should be interpreted as “having at least,” the term“includes” should be interpreted as “includes but is not limited to,”etc.). It will be further understood by those within the art that if aspecific number of an introduced claim recitation is intended, such anintent will be explicitly recited in the claim, and in the absence ofsuch recitation no such intent is present. For example, as an aid tounderstanding, the following appended claims may contain usage of theintroductory phrases “at least one” and “one or more” to introduce claimrecitations. However, the use of such phrases should not be construed toimply that the introduction of a claim recitation by the indefinitearticles “a” or “an” limits any particular claim containing suchintroduced claim recitation to embodiments containing only one suchrecitation, even when the same claim includes the introductory phrases“one or more” or “at least one” and indefinite articles such as “a” or“an” (e.g., “a” and/or “an” should be interpreted to mean “at least one”or “one or more”); the same holds true for the use of definite articlesused to introduce claim recitations. In addition, even if a specificnumber of an introduced claim recitation is explicitly recited, thoseskilled in the art will recognize that such recitation should beinterpreted to mean at least the recited number (e.g., the barerecitation of “two recitations,” without other modifiers, means at leasttwo recitations, or two or more recitations). Furthermore, in thoseinstances where a convention analogous to “at least one of A, B, and C,etc.” is used, in general such a construction is intended in the senseone having skill in the art would understand the convention (e.g., “asystem having at least one of A, B, and C” would include but not belimited to systems that have A alone, B alone, C alone, A and Btogether, A and C together, B and C together, and/or A, B, and Ctogether, etc.). In those instances where a convention analogous to “atleast one of A, B, or C, etc.” is used, in general such a constructionis intended in the sense one having skill in the art would understandthe convention (e.g., “a system having at least one of A, B, or C” wouldinclude but not be limited to systems that have A alone, B alone, Calone, A and B together, A and C together, B and C together, and/or A,B, and C together, etc.). It will be further understood by those withinthe art that virtually any disjunctive word and/or phrase presenting twoor more alternative terms, whether in the description, claims, ordrawings, should be understood to contemplate the possibilities ofincluding one of the terms, either of the terms, or both terms. Forexample, the phrase “A or B” will be understood to include thepossibilities of “A” or “B” or “A and B.”

In addition, where features or aspects of the disclosure are describedin terms of Markush groups, those skilled in the art will recognize thatthe disclosure is also thereby described in terms of any individualmember or subgroup of members of the Markush group.

As will be understood by one skilled in the art, for any and allpurposes, such as in terms of providing a written description, allranges disclosed herein also encompass any and all possible subrangesand combinations of subranges thereof. Any listed range can be easilyrecognized as sufficiently describing and enabling the same range beingbroken down into at least equal halves, thirds, quarters, fifths,tenths, etc. As a non-limiting example, each range discussed herein canbe readily broken down into a lower third, middle third and upper third,etc. As will also be understood by one skilled in the art all languagesuch as “up to,” “at least,” and the like include the number recited andrefer to ranges which can be subsequently broken down into subranges asdiscussed above. Finally, as will be understood by one skilled in theart, a range includes each individual member. Thus, for example, a grouphaving 1-3 cells refers to groups having 1, 2, or 3 cells. Similarly, agroup having 1-5 cells refers to groups having 1, 2, 3, 4, or 5 cells,and so forth.

From the foregoing, it will be appreciated that various embodiments ofthe present disclosure have been described herein for purposes ofillustration, and that various modifications may be made withoutdeparting from the scope and spirit of the present disclosure.Accordingly, the various embodiments disclosed herein are not intendedto be limiting, with the true scope and spirit being indicated by thefollowing claims.

1. A method performed under control of a mobile device, the methodcomprising: receiving, from an access point, a first signal transmittedat a first frequency band; receiving, from the access point, a secondsignal transmitted at a second frequency band; measuring a differencevalue between propagation properties of the first signal and the secondsignal; and identifying whether a propagation path between the mobiledevice and the access point is line-of-sight or non-line-of-sight basedat least in part on the difference value.
 2. The method of claim 1,wherein the receiving of the second signal is performed concurrentlywith the receiving of the first signal.
 3. The method of claim 1,wherein at least one of the first signal or the second signal includeslocation information of the access point, and wherein the method furthercomprises: calculating a current position of the mobile device based atleast in part on the location information of the access point.
 4. Themethod of claim 3, wherein the calculating of the current position ofthe mobile device is performed when the identifying indicates that thepropagation path between the mobile device and the access point isline-of-sight.
 5. The method of claim 1, further comprising:transmitting, to the access point, a probe request signal at the firstfrequency band, wherein the first signal is a probe response signal inresponse to the probe request signal.
 6. The method of claim 1, furthercomprising: receiving, from the access point, a propagation environmentsignal transmitted at the first frequency band, wherein the propagationenvironment signal includes at least one of information about a layoutof a building, in which the access point and the mobile device arelocated, or information about materials of the building, and wherein theidentifying is further based at least in part on the propagationenvironment signal.
 7. The method of claim 1, wherein the first andsecond signals include a beacon signal.
 8. The method of claim 1,wherein the measuring of the difference value comprises measuring thepropagation properties of the first and second signals.
 9. The method ofclaim 1, wherein the propagation property is one selected from a groupconsisting of a propagation loss, a reflection property, a diffractionproperty and an absorption property.
 10. The method of claim 1, whereinthe access point is a wireless-fidelity (Wi-Fi) access point.
 11. Themethod of claim 1, wherein the first frequency band is an ISM(Industry-Science-Medical) band and the second frequency band is a UNII(Unlicensed National Information Infrastructure) band.
 12. A mobiledevice, comprising: a receiver unit configured to receive, from anaccess point, a first signal transmitted at a first frequency band and asecond signal transmitted at a second frequency band; a difference valuecalculation unit configured to calculate a difference value betweenpropagation properties of the first signal and the second signal; anidentification unit configured to identify whether a propagation pathbetween the mobile device and the access point is line-of-sight ornon-line-of-sight based at least in part on the difference value; and aposition calculation unit configured to calculate a current position ofthe mobile device based at least in part on the first signal and/or thesecond signal.
 13. The mobile device of claim 12, wherein the receiverunit is further configured to receive the first signal and the secondsignal concurrently.
 14. The mobile device of claim 12, wherein at leastone of the first signal or the second signal includes locationinformation of the access point, and wherein the position calculationunit is further configured to calculate the current position of themobile device based at least in part on the location information of theaccess point.
 15. The mobile device of claim 14, wherein the positioncalculation unit is further configured to calculate the current positionof the mobile device when the identification unit identifies that thepropagation path between the mobile device and the access point isline-of-sight.
 16. The mobile device of claim 12, wherein the receiverunit is further configured to receive, from the access point, apropagation environment signal transmitted at the first frequency band,wherein the propagation environment signal includes at least one ofinformation about a layout of a building, in which the access point andthe mobile device are located, or information about materials of thebuilding, and wherein the identification unit is further configured toidentify the propagation path based at least in part on the propagationenvironment signal.
 17. The mobile device of claim 12, wherein the firstand second signals include at least one of a probe response signal or abeacon signal.
 18. The mobile device of claim 12, wherein thepropagation property is one selected from a group consisting of apropagation loss, a reflection property, a diffraction property and anabsorption property.
 19. The mobile device of claim 12, wherein theaccess point is a Wi-Fi access point, and wherein the first frequencyband is an ISM (Industry-Science-Medical) band and the second frequencyband is a UNII (Unlicensed National Information Infrastructure) band.20. A non-transitory computer-readable storage medium having storedthereon computer-executable instructions that, in response to execution,cause a mobile device to perform operations, comprising: transmitting,to an access point, a probe request signal at a first frequency band;receiving, from the access point, a probe response signal transmitted atthe first frequency band in response to the probe request signal;receiving, from the access point, a beacon signal transmitted at asecond frequency band; measuring a difference value between propagationproperties of the probe response signal and the beacon signal; andidentifying whether a propagation path between the mobile device and theaccess point is line-of-sight or non-line-of-sight based at least inpart on the difference value.
 21. The computer-readable storage mediumof claim 20, wherein at least one of the probe response signal or thebeacon signal includes location information of the access point, andwherein the operations further comprise: calculating a current positionof the mobile device based at least in part on the location informationof the access point.
 22. The computer-readable storage medium of claim20, wherein the propagation property is one selected from a groupconsisting of a propagation loss, a reflection property, a diffractionproperty and an absorption property.
 23. The computer-readable storagemedium of claim 20, wherein the access point is a Wi-Fi access point,and wherein the first frequency band is an ISM(Industry-Science-Medical) band and the second frequency band is a UNII(Unlicensed National Information Infrastructure) band.